1. Field of Invention
The present invention relates to combination locks and more particularly to a combination lock capable of being opened by inserting a key into keyhole in addition to turning tumbler wheels to a set series of numbers for opening.
2. Related Art
Combination locks and padlocks are two different types of lock and a great difference with respect to construction thus exists between them. Also, disclosures about combined combination lock and padlock were not available several years ago as far as the present invention is aware.
U.S. Pat. No. 6,792,778 to Chen, entitled “Combination Lock” is specifically incorporated herein by reference. This patent is assigned to Glox Industry Co., Ltd., assignee of the subject invention. Shackle disclosed in this patent is not the same as one disclosed in the invention as explained later. Moreover, associated construction of the shackle must be redesigned in order to facilitate opening or locking of the lock. The invention is thus addressed to provide a solution to the above.